I am making an E commerce site, I want to store Cart elements in an integer Array Field. I am using PostGreSql as my database. I have created model for cart by extending Django User model. Here is my models class UserCart(models.Model): user=models.OneToOneField(User,on_delete=models.CASCADE) user_product=models.IntegerField(blank=True, null=True) cart_products = ArrayField( models.IntegerField(blank=True), default = list ) User.profile = property(lambda u:UserCart.objects.get_or_create(user=u)[0]) Below is my Form.py. I have created only basic form from django import forms from .models import UserCart from django.db import models from django.contrib.postgres.fields import ArrayField class UserCartForm (forms.ModelForm): class Meta: model= UserCart fields = ('user_product',) I have searched alot on internet but was unable to find the relevant answer.I want that whenever user clicks on Add to Cart button, that product_id gets stored in cart_products array.I read somewhere that ArrayFields behave as list in Django, so here is my views.py @login_required def user_cart(request): if request.method=='POST': form=UserCartForm(request.POST , instance=request.user.profile) if form.is_valid(): post = form.save(commit=False) post.cart_products.append(99) post.save() return HttpResponseRedirect('/user_login/loggedin') else: HttpResponse("Error") else: user=request.user profile=user.profile form= UserCartForm(instance=profile) args={} args.update(csrf(request)) args['form']=form return render_to_response('cartapi.html' ,args) Its giving me Error that AttributeError at /cart/ac/ 'NoneType' object has no attribute 'append' Request Method: POST Request URL: http://localhost:8000/cart/ac/ Django Version: 1.11.2 Exception Type: AttributeError Exception Value: 'NoneType' object has no attribute 'append' Exception Location: C:\Users\Muhammad Jawad\AppData\Local\Programs\Python\Python36-32\mysite\cart\views.py in user_cart, line 19 Python Executable: C:\Users\Muhammad Jawad\AppData\Local\Programs\Python\Python36-32\python.exe And if i save cart_products this way post.cart_products=99 Then it throws this error column "cart_products" is of type int4range but expression is of type integer LINE 1: ...er_id" = 1, "user_cart" = 3000, "cart_products" = 99 WHERE "... ^ HINT: You will need to rewrite or cast the expression. Request Method: POST Request URL: http://localhost:8000/cart/ac/ Django Version: 1.11.2 Exception Type: ProgrammingError Exception Value: column "cart_products" is of type int4range but expression is of type integer LINE 1: ...er_id" = 1, "user_cart" = 3000, "cart_products" = 99 WHERE "... ^ HINT: You will need to rewrite or cast the expression. Kindly Help me in this matter.Summarizing my Question: How can i get user_product as id and save it in cart_products Continue reading...
